1. Field of the Invention
This invention relates to laser aiming systems for assisting the aiming of firearms, and in particular, to a control circuit arrangement for a laser aiming system.
2. Description of the Prior Art
Laser assisted aiming systems for weapons are known in the art. For example, U.S. Pat. No. 4,026,054, issued to the inventor of the instant invention, discloses and claims a laser aiming system including a self-contained power supply module and laser tube. Further, application Ser. No. 717,349, filed Aug. 24, 1976, now U.S. Pat. No. 4,079,534, in the name of the inventor of the instant invention relates to a laser sighting apparatus for interchangeably attaching laser aiming devices to weapons.
The circuit arrangements utilized in the aiming devices of the above-referenced patent and application utilize a source of electrical potential, typically a D.C. battery, connected in series to a high voltage power supply element. The power supply converts the D.C. signal from the battery to a high voltage, low current signal which is impressed across a coherent light beam generating tube, or laser head. In addition to a manually operated on-off switch, appropriate governmental regulations require the disposition of safety switches in each of the leads connecting the battery to the high voltage supply. Magnetically responsive reed switches have been found to be of particular utility for such safety switches.
As is known by those skilled in the art, a reed switch comprises two overlapping, flat, cantilevered ferromagnetic reeds sealed in an inert gas environment in a glass envelope. The presence of a magnetic field causes the overlapped ends of the reeds to close a slight air gap defined therebetween to provide current-conducting contact therebetween. In the laser aiming systems of the above-referenced patent application, a permanent magnet is inserted into a suitable aperture provided in the aiming system housing to thereby control the closure of one of the magnetically responsive reed switches. A second permanent magnet is mounted in a predetermined orientation on a trigger-like member and brought into a position where the magnet effects the closure of the second reed switch by a finger movement of a marksman similar to the finger movement by which the trigger of the firearm is depressed. That is, movement of the trigger finger of the marksman mechanically actuates the toggle of the aiming device carrying the second permanent magnet to bring that magnet into proximity to the second reed switch. With the second magnet so positioned the control circuit of the aiming device is completed (assuming the manual on-off switch has been actuated) to initiate the generation of the laser beam to assist the marksman in sighting and aiming the weapon. Continued finger movement of the marksman then, of course, engages and depresses the trigger to fire the weapon.
It has, however, been observed that despite the release of the mechanical toggle and the withdrawal of the second magnet from proximity to the second reed switch the laser beam continues to be generated. This has the deleterious consequence of prematurely draining the battery. Furthermore, in some situations, the exposure of the firing location of the marksman may also be disadvantageous.
The continued contact between the flaps of the reed switch after the removal of the permanent magnet associated therewith is believed to be caused by the presence of switching transient current signals from the high voltage supply riding on D.C. current signals from the battery. These switching transient current signals are believed to induce a magnetic field of sufficient intensity about the current carrying leads, including the flaps of the reed switch, to maintain the switch closed even after the removal of the permanent magnet.
Accordingly, it would be advantageous to provide a control circuit arrangement for a laser aiming system wherein the magnetically responsive reed switches are magnetically decoupled from the high voltage power supply. That is to say, it would be advantageous to provide a control circuit arrangement for a laser aiming device wherein switching transient current signals believed to emanate from the high voltage power supply are reduced so that magnetic fields induced thereby are of an intensity insufficient to maintain the magnetically responsive reed switches in a closed state despite the withdrawal of a permanent magnet actuator associated with the reed switch.